Field of Endeavor
The present application relates to Raman spectroscopy and more particularly to surface-enhanced Raman spectroscopy (SERS).
State of Technology
This section provides background information related to the present disclosure which is not necessarily prior art.
Surface enhanced Raman spectroscopy (SERS) has attracted considerable interest since its discovery and highlighted single-molecule detection. This interesting phenomenon has been primarily explained by two theories: electromagnetic effect and chemical effect. The chemical enhancement theory is explained through charge transfer complex formation that requires a chemical bond between the molecule and the surface. Electromagnetic enhancement theory, on the other hand, is associated with a local electromagnetic field enhanced by excited surface plasmons on a metal surface, featured by the fourth power field enhancement. The main objective for many researchers has been to fabricate a substrate that can provide a large number of sites of strong field enhancement, so called hotspots. Methods of achieving this target involve localization (sharp tips), coupling (narrow or slightly touching gaps), and resonance (regularity of the metal structure) of surface plasmons, practically enabled by advanced nanomanufacturing techniques.